Yes, this is not a problem.
You simply need to configure the name servers for your domains, using whatever configuration utility your registrar provides, to the following...
Once you have done this, you can add the domain to the DreamHost system via the admin panel and a web-directory will be created for that domain, which you can upload your site files to.
Note: After making the DNS changes it will take up to 72 hours for the new DNS information to propagate across the Internet and your domains to be reachable.
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